1. Field of the Invention
The present invention relates to a cleat for an athletic shoe that provides both traction on greens and on hard smooth surfaces in a substantially non-penetrating manner, and particularly to a non-metal cleat having dual traction elements of different hardness including a center region that is less dense than the surrounding portion of the cleat.
2. Background
Spikes or cleats for athletic shoes have long been used to provide traction in dirt and grass. Such spikes or cleats typically have been made of metal or other relatively hard materials. However, various structures for cleats have been suggested including cleats having a hard metal center surrounded by an elastomeric material.
It was often found when using non-metal cleats on athletic surfaces, particularly artificial turf, that the cleats of an athletic shoe would be subject to increased wear do to the harder surface. In order to combat such wear, cleats were made with a harder insert supported by a relatively softer cleat body. Flemming (U.S. Pat. No. 4,833,796) discloses one such example of such an arrangement. In this arrangement, a relatively stiff elastic cleat body holds a ceramic insert. In this manner, the ceramic portion, which is relatively very hard, makes contact with the playing surface, while the supporting stiff elastic cleat body allows for flexibility and therefore less stressful dynamic loading of the athlete's foot.
Flemming's cleat, however, does not solve a problem often encountered by golfers. That is the need to walk not just over greens, but also over smooth hard surfaces peripheral to the playing area. Like traditional metal cleats, on a hard smooth surface, the Flemming cleat provides little traction and also does not address the additional problems of scratching the surfaces that are walked on, which in some areas peripheral to a golf course is of some concern.
A further problem is pointed out by Deacon et al. (U.S. Pat. No. 5,259,129). In the winter months, present day golfers are frequently not allowed to wear penetrating cleats so as not to damage the grass on the course. Deacon proposes a non-metal disk-shaped winter cleat insert for a pair of golfing shoes in order to replace the conventional metal spikes that provide traction on turf without penetrating or damaging the grass. These inserts, however, are not designed for walking on hard surfaces, and doing so wears rapidly on the radial gripping ridges and decreases traction during a golf swing.
Thus, improvements in cleats for athletic shoes, and particularly for golf shoes, are still being sought.